In 1986 a new virus designated as HIV-2 was isolated from West African AIDS patients Clavel et al., Science 233, 343-346 (1986); Clavel et al., Nature 324, 691-695 (1986)!. On the basis of its morphology, its lymphotropism and its cytophatic in vitro activity on T.sub.4 -positive cells, this virus was associated with the AIDS-causing HIV-1 viruses. In spite of these similiar properties, a genetic comparison of HIV-1 and HIV-2 viruses showed, however, only a limited sequence homology Guyader et al., Nature 326, 662-669 (1987)!.
More than 20 different HIV-2 viruses have been isolated from West African AIDS patients and from European AIDS patients Guyader et al., supra; Brun-Vezinet et al., Lancet 1, 128-132 (1987)!. The sera of these AIDS patients were all negative in the HIV-1 ELISA Brun-Vezinet et al., supra!. Accordingly, there is a very great need for a precise and rapid method for the diagnosis of HIV-2 viruses in human blood and in other body fluids.